176 TEK KNTOJIOLOOrSx's RECORD. 



to a minimum. When this is so, a fresh layer of chitin appears to be 

 formed on the surface of the hypodermis, and, after a variable period 

 of time, the old skin, consisting entirely of waste matter and dead 

 cells, is cast off. If chitin, as has been supposed, really consists of 

 the waste matters of the blood, it renders easy of explanation facts 

 connected with excretion, which would be otherwise most difficult to 

 understand." 



" Histolysis. Our observations on the state of the tissues of the 

 pronymph of the blowfly whilst in the pupal stage give us material 

 for reflection as to the changes which take place in the pupal stage of 

 other insects, and, if we examine the condition of the tissues of the 

 pupa; of butterflies and moths at successive intervals, we shall find 

 somewhat analogous characters presented. First, there will be the 

 breaking down of the tissues, or histolysis, as it is termed ; then there 

 will be the rehabilitation of the tissues, or histogenesis, during which 

 the tissue is formed anew into the various organs. Histogenesis is, 

 of course, largely dependent on histolysis, since the material used in 

 the rebuilding of the tissues must be obtained from the material which 

 has resulted from previous destruction. During the resting period of 

 the larva and the first stage of the pupal period, histolysis is in the 

 ascendant, whilst in the later pupal stages histogenesis is predominant. 

 The destruction of the tissues is carried on in a remarkable manner. 

 Viallanes explains fully how certain cells, called phagocytes, not unlike 

 the white corpuscles of the blood, enter the tissues which are to be 

 disintegrated. Here the cells become distended, a pseudo-inflammatory 

 process takes place in the tissues, and, at the same time, the larval 

 tissues are broken up and assume a creamy-looking appearance, whilst 

 the buds or germs from which the new organs are to be developed are 

 exempt from the destruction. Of these germs more than sixty have 

 been already detected, and once their growth commences, progress is 

 usually rapid. Certain organs and structures are in progress of 

 rehabilitation, whilst others are undergoing histolysis. There is much 

 yet to be learned of the processes of histolysis and histogenesis, but 

 there can bo no doubt that they are very general among all insects in 

 this stage, and are, according to Sharp, probably only exaggerated 

 forms of the phenomena of the ordinary life of tissues, due to greater 

 rapidity and discontinuity of tissue nutrition. It is worthy of notice, 

 that the regenerative buds to which we have referred, and also the 

 rudimentary sexual glands, are derived directly from the embryo, and 

 do not undergo histolysis, but remain in a comparatively embryonic 

 condition during the whole period of the growth of the larva, and 

 histolysis of the tissues. When these processes are complete, these cells, 

 utilizing the prepared material now at their disposal, rapidly grow 

 and come to maturity, and, on the completion of the various parts, 

 produce the perfect insect." 



Report of the Entomological Department of the New Jersey 

 Agricultural College Experiment Station. By John B. Smith, D.Sc. 

 [Trenton, New Jersey, 1896.] — This volume is most interesting, not 

 only to economic entomologists, but also to systematists and general 

 students. The chapter entitled, " The relation of insects to fruits," 

 is remarkably interesting. The illustrations are both numerous and 

 well-executed. 



Errata. — p. 151, line 4, for "third oblique," read "Jimt oblique"; ]). 138, 

 line 11, for " Chrysoccphala,^' read " Physocephala," 



